Treatment of cellulose derivative materials



Jan. 3, 1939.

R. W. MONCRIEFF ET AL TREATIIJENT OF CELLULOSE DERIVATIVE MATERIALSFiled Dec. 2'7. 193'? Patented Jan. 3, 1939 TREATMENT OF OELLULOS EDERIVATIVE Bobert'Wighton Moncrlei! and Frank Brentnall Hill, Spondon,near Derb England, assignors to Celanese corporation oi. America, acorporation Delaware Application Mma. :1, 1937, Serial No. 181,78

In Great Britain January is, 11m

scum.

This invention relates to improvements in the treatment of cellulosederivative materials, and particularly to improvements in processeswherein cellulose derivative filaments, yarn and similar materials arestretched.

In U. 8. application 8. No. 69,282, filed March 17, 1936, apparatus forstretching artificial filaments and similar materials in the presence ofsteam is described, which comprises a steam stretching chamber and anend pressure chamber for inert fluid connected therewith. -Thespecification also'describes a process of stretching using thisapparatus in which the end pressure chamber contains compressed air orother inert gas.

It has now been discovered that the use of water in the end chamberimproves the voluminosity oi the product, especially if the water isemployed at a pressure slightly greater than W that of the steam.

According to the present invention therefore artificial filaments, yarnsand similar materials made of cellulose acetate or other organicderivative of cellulose are passed through an end 5 pressure chambercontaining water in substan:-

tially non-slipping contact with a positively driven reed devicecontained in the chamber and then through saturated or wet steam at atemperature above 100 C. in a steam chamber,

stretching being effected during the passage of the materials throughthe steam chamber.

The water is preferably circulated continuously through the end pressurechamber in order that it may be maintained at a constant temperature.The invention is particularly COR-r cerned with the use of water atapproximately room temperature, e. g., -30 C., and while it may beemployed at higher temperatures its temperature should not be so high asto bring the materials into a condition such that stretching takes placeprior to their entering the steam stretching chamber.

The pressure of the water in the end chamber may be the same as that ofthe steam in the stretching chamber or below or above this Dressure. Anydifierence between the pressures in the two chambers is, however,preferably small in any case, for example of the order or 1 or 2 up to 5or 6 pounds per square inch.

The feed device contained in the end chamber may be a positively drivenroller in combina-- tion with two guide bars or two or more positivelydriven rollers .not in contact with; each other, the combination ofroller and guide bars or of rollers being so arranged that the angle oi.

lap of the materials on the roller or rollers is such that there issubstantially no slip. Alternatively,;twoor more driven rollers whichare in contact'with each other-may be employed, the yarn passing throughthe nip or nips oi the rollers.

Saturated or wet steam may be employed in the steam stretching chamberat a temperature of, for example, or C. or more, and the pressure oi thewater in the end chamber may, torexamplabe 15, 25 or 35 pounds persquare inch or more. In order to increase the wetnessoi the steam watermay be sprayed into the steam chamber through one or more sprayspositioned therein, e. g., near the yarn inlet. On the other hand, goodresults may be obtained without the use of the spray. I

The materials may be sprayed with cold water immediately on issuing fromthe steam stretching chamber in order that the action of the steam maybe sharply confined to the materials during their passage through thestretching chamber. a

The position oi the end-box and stretching chamber maybe such that thematerials pass through the apparatus substantially in a horizontalplane, or it may be such that they follow a path which. is inclined. tothe horizontal, e. g., at 45 (2., or which is vertical.

The accompanying drawing illustrates diagrammatically anapparatus whichmay be employed in carrying out the process of the present invention, 7i

Figure 1 being a longitudinal cross-section of the apparatus, and

Figure 2 a cross-section on the line 22 of Fis- 1.

In carrying out the process of the present invention using the apparatusillustrated in the accompanying drawing, a number of threads-I from acreel of bobbins 2 pass over a guide and through orifices 3 into an endchamber 4. In the end chamber they pass in contact with a .feed device5, and then through orifices 6 into a steam chamber 1 from which theyemerge through orifices I and pass in contact with a stretching device 0and over a guide to a creel Y or bobbins Ill.

The end chamber 4 which is provided with a pressure gauge I2 is filledwith water under pressure through the inlet II, the rate of flow oi thewater being regulated by means of the valve on the outlet pipe 14. Steamis introduced into the steam chamber 1 through the steam inlets II, andthis chamber ,is provided with a pres-- it in any way.

Example 1 Dry spun cellulose acetate yarn is passed in contact with afeed device contained in an end chamber through which water is passedunder pressure, and then from the end chamber into and through a steamchamber in which it is stretched by means of a positively drivenstretching device positioned outside the steam chamber. The water passedthrough the end chamber is at approximately atmospheric temperature andunder a pressure of about 36 pounds per square inch, while the steam,which is wet, is under a pressure of about 38 pounds per square inchgauge. The length of the steam chamber is about 9 inches,- and the yarnis stretched to about 10 times its original length.

Example 2 'exception that the water pressure is about pounds per squareinch below that of the steam.

Example 3 Dry spun cellulose acetate yarn is stretched as described inExample 1, with the exception that the water pressure is about /2 poundper square inch above that of the steam.

In each case a product having a considerably increased tenacity isobtained.

The properties of the materials, and particularly their tenacity andextensibility, may be varied considerably by variation of the stretchingconditions, for example the temperature of the steam employed, therelation between the pressure of the steam in the steam chamber and thewater in the end chamber, the degree 01' stretch, the size and number ofthe steam inlets and the length of the steam chamber. For example, bysuitable variation of the conditions cellulose acetate yarns having atenacity of 2, 4 or 5 grams per denier or even more may be obtained.

While the present invention is of particular importance in the treatmentof materials made of cellulose acetate, it may alsobe employed in thetreatment of materials made of other organic derivative of cellulose,for example cellulose propionate, butyrate and nitro-acetate, andmethyl, ethyl and butyl celluloses.

Having described our invention, what we desire to secure by LettersPatent is: '51. Process for the treatment of artificial materials, whichcomprises passing artificial filaments, yarns and similar materials madeof organic derivatives of cellulose through a body of water undersuperatmospheric pressure in an end pressure chamber and insubstantially non-slipping contact with a positively driven feed devicecontained in the chamber and then through saturated or wet steam at atemperature above 100 C. in a steam chamber, and stretching thematerials during their passage through the steam chamber.

2. Process for the treatment of artificial materiais, which comprisespassing artificial filaments, yarns and similar materials made ofcellulose acetate through, a body of water under superatmosphericpressure in an end pressure chamber and in substantially non-slippingcontact with a positively driven feed device contained in the chamberand then through wet steam at a temperature above 100 C. in a steamchamber, and stretching the materials during their passage through thesteam chamber.

3. Process for the treatment of artificial materials, which comprisespassing artificial filaments, yarns and similar materials made oforganic derivatives of cellulose through a body of water undersuperatmospherio pressure in an end pressure chamber and. insubstantially non-slipping contact witlr a positively driven feed devicecontained in the chamber and then through saturated or wet steam at atemperature above 100 C. in a steam chamber, and stretching thematerials during their passage through the steam chamber, the differencein pressure between the water and steam being 5 lbs. per square inch orless.

4. Process for the treatment of artificial materials, which comprisespassing artificial filaments, yarns and similar materials made ofcellulose acetate through a body of water under superatmosphericpressure in an end pressure chamber and in substantially non-slippingcontact with av positively driven feed device contained in the chamberand then through wet steam at a temperature above 100 C. in a steamchamber, and stretching the materials during their passage through thesteam chamber, the difference in pressure between the water and steambeing 5 lbs. per square inch or less.

5. Process for the treatment of artificial mas terials, which comprisespassing artificial filaments, yarns and similar materials made oforganic derivatives of cellulose through a body of water undersuperatmospheric pressure in an end pressure chamber.and insubstantially nonslipping' contact wtih a positively driven feed devicecontained in the chamber and then through saturated or wet steam at atemperature above 130 C. in a steam chamber, and stretching thematerials during their passage through the steam chamber, the differencein pressure between the water and steam being 5 lbs. per square inch orless.

6. Process for the treatment of artificial materials, which comprisespassing artificial filaments, yarns and similar materials made ofcellulose acetate through a body of water under superatmosphericpressure in an end pressure chamber and in substantially non-slippingcontact with a positively driven feed device contained in the chamberand then through wet steam at a temperature above 130 C. in a steamchamber, and stretching the materials during their passage through thesteam chamber, the difference in pressure between the water and steambeing 5 lbs. per square inch or less.

7. Process for the treatment of artificial materials, which comprisespassing artificial. filaments, yarns and similar materials made oforganic derivatives of cellulose through a body of water undersuperatmospheric pressure at a temperature of 30 C. or less in an endpressure chamber and in substantially non-slipping contact with apositively driven feed device contained in the chamber and then throughsaturated or wet steam at a temperature above 100 C. in a steam chamber,and stretching the materials during their passage through the steamchamber.

8. Process for the treatment of artificial materials, which comprisespassing artificial filaments, yarns and similar materials made of cel-'lulose acetate through a body of water under superatmospherlc pressureat a temperature of 30 C. or less-in an end pressure chamber and insubstantially non-slipping contact with a positively driven feed devicecontained in the chamber and then through wet steam at a temperatureabove 100 C; in a steam chamber, and stretching the materials duringtheir passage through the steam chamber, the difference in pressurebetween the water and steam being 5 lbs. persquare inch or less.

9. Process for the treatment of artificial materials, which comprisespassing artificial filaments, yarns and similar materials made of cel-CERTIFICATE OF CORREG I'I 0N Patent No. 2,1) 2, 912.

ROBERT WIGH'ION MONCRIEFF ET AL.

superatmospheric pressure at a temperature of 30 C. or less in an endpressure chamber and in substantially non-slipping contact with apositively driven feed device contained in the chamber and then throughwet steam at a temperature above 130 C. in a steam chamber. andstretching the materials during their e through the steam chamber, thediflerence in pressure between the water and steam being-1o 5 lbs. persquare inch or less.

ROBERT WIGH'ION MONCRIEFF. FRANK BRENTNALL HILL.

January 3, 1939.

' .It is hereby certified that error appears in theprinted specificationof the above numbered patent requiring correctionas follows: Page 2,first column, line 17, after the word "inc h" insert gauge; and" secondcolumn, line 75, claim 8, for the syllable cel-" read cellulose acetatethrough a body of water under; and that the said Letters Patent shouldberead with' this correction therein that the same may conform to therecord of the case in the Patent Office.

Signed and sealed this 7th day of Harch, A. D. 1939.

(seal) Henry Van arsdale.

Acting Commissioner of Patents.

